Straight communication between Siemens S7 TCP/IP port and PC software

pietervdb · Jun 23, 2009

Hello,

We have a client where we must replace an old Omron PLC with new Siemens S7 PLC.
The Omron PLC is connected through a RS232 connection with a custom made ERP packet.

The Omron runs as a slave connection and the ERP packet is continuous polling the port on the PLC. The ERP keeps asking the status of the machine and the PLC gives the status. In case of an event it sends data back to the PLC where the PLC takes over and perform some actions. Basically sending over strings form the PLC to the ERP and vice versa.

Now we want to use a TCP/IP connection for sending the data (strings) to the ERP software.
We have a Siemens CPU with a PN port onboard and now I’m looking for some FB/FC’s where I can listen to the TCP/IP port and put some data on the port.

The ERP software is adjusted that it sends his data directly to the IP address from the Siemens CPU.
Does anyone has done this before? Or does someone has some examples?

Thanx

JesperMP · Jun 23, 2009

Can the ERP software use OPC ?
That would seem the most straightforward.

There is a possibility with lower level comms via Send/Receive.
But it will take more effort, and you are on your own.

And, maybe you should drop the strings for regular tag addresses.
The dependency on strings may be because that suited the old systems serial comms best.

pietervdb · Jun 23, 2009

I don't think the ERP knows how to use OPC. I suggested it but i think they don't want to change much in the (old) ERP software.

The ERP software looks DOS based with a Windows jacket.

I think i gonne use the send/recieve protocol from Siemens. Any Examples?

JesperMP · Jun 23, 2009

Check up on the open communication blocks, TCON, TDISCON, TSEND, TRCV.

You probably have to experiment a bit to get it to work. I cannot help much I am afraid.
Also, you may have to modify the ERP side.

If this is impossible you may consider to make the same serial connection to the new S7 as was used with old Omron. There is the CP340 which can speak ASCII.

dchartier · Jun 24, 2009

Hello Pieter;
You could start by looking at the following Siemens FAQ:
How do you program the communication blocks FB63 "TSEND", FB64 "TRCV", FB65 "TCON" and FB66 "TDISCON" in order to use the TCP protocol for data exchange via the integrated Industrial Ethernet interface of an S7-300 or S7-400 CPU?

http://support.automation.siemens.com/WW/view/en/29737950

This should give you good enough starting info on "how" this can be done; then you can devise your own specifics to meet your application needs.

Hope this helps,
Daniel Chartier

pietervdb · Jun 24, 2009

Thanx, i'm gonne try it.

P.

dimmitrisd · Dec 23, 2014

Problem

pietervdb said:
P.

Hallo dear friend. I wonder whether you found a solution. I'm desperate in a quite same problem and I need urgent help on that.
Please I need your help

Straight communication between Siemens S7 TCP/IP port and PC software

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